Notes:
Summary Kaposi's sarcoma (KS) in human immunodeficiency virus infection (HIV) has become a rather frequent manifestation of the previously rare disease with fatal outcome. Initial lesions of KS were studied by means of histopathology, immunohistology, and electron microscopy in order to define the earliest alterations. The histopathological changes of initial lesions were distinct, consisting of (1) discrete proliferation of capillary vessels, (2) dissection of collagen by proliferating spindle cells which formed slits, (3) atypical spindle cells arranged in an Indian file pattern, and (4) the lack of any inflammatory cellular infiltrate. Double staining with antibodies against vimentin and immunohistochemical markers for endothelial cells revealed that slits forming vimentin-positive spindle cells displayed laminin, factor VIII, and PAL-E. Atypical vimentinpositive spindle cells arranged in an Indian file pattern inconsistently expressed laminin and factor VIII, but not PAL-E. KS cells rarely stained with the lectin UEA I, not even in case of less advanced dedifferentiation. Electron microscopy showed gradual transformation between spindle cells forming slits and those having lost the ability to form incomplete vessel walls. The present findings support the view that KS develops from the endothelial cells of the blood vessels. The proliferation of atypical endothelial cells as early as in initial lesions and the lack of inflammation favors the primary neoplastic genesis of KS.

Notes:
Summary Cytochrome P-450-dependent arylhydrocarbon-hydroxylase (AHH) activity and inducibility by benzanthracene (BA) was measured in cultured guinea pig and human epidermal cells. Basal AHH-activity (AHHb) in guinea pig epidermal cells was much higher than in human epidermal cells. AHHb in guinea pig epidermal cells was directly related to the labeling index and decreased to the original level between the 5th and 7th day of cell culturing. On the other hand, the induction-ratio of AHH reached its maximum level when the number of cells began to rise (proliferation phase) and remained high at day 7 of the cell culture. These results suggest a cell growth dependent activity and inducibility of carcinogen-metabolizing enzymes, such as AHH, in isolated epidermal cells.

Notes:
Summary The specific activity of myeloperoxidase (MPO), an enzyme located in the primary granules of polymorphonuclear leukocytes, was measured in patients with psoriasis vulgaris and compared with that in patients with atopic dermatitis and in healthy subjects. MPO catalyzes the oxidation of guaiacol into tetraguaiacol in the presence of H2O2. The activity was determined by photometric measurement of tetraguaiacol. The specific MPO activity showed no statistically significant difference between the healthy subjects and the patients with atopic dermatitis. In comparison to these two groups the specific MOP activity of the psoriatic patients showed a slight reduction which was, however, not statistically significant.